Air foam complex flooding used to improving oil recovery was feasible and effective method in low permeability and high salinity reservoir of Changqing oilfield. The effect of strata medium, such as high salinity formation water and oil etc, on the foaming and steady performance of eight foaming agents, and the effect of foaming agent on the surface tension and viscosity of crude oil and high salinity formation water were evaluated. The eight different foaming agents were sodium alcohol ether sulphate, cocoamidopropyl betaine, sodium dodecyl benzene sulphonate, octaphenyl polyoxyethyiene (TX-10), alkylphenol ethoxylates (OP-10), coconutt diethanol amide 6501, alcohol ether carboxylate, FLH nonionic osmotic agent, which were numbered consecutively from 1 to 8. The injected water type of Changqing oilfield was Na₂SO₄, with 1.1 g/L salinity and 6.5 pH value. The formation water type was CaCl₂ with 82.2 g/L salinity and 5.95 pH value. The density of crude oil was 0.85 g/cm³, and the viscosity was 6 mPa·s. Experiment results indicated that No. 6—8 foaming agents were not compatibility with formation water. No. 1—5 foaming agents reduced the surface tension of injected water and formation water by half. And there was no influence on surface tension and viscosity of crude oil. When injected water was changed to a combination of injected water and formation water in volume ratio 1:1, the foam volume of No. 1—5 foaming agents changed a little, and there was no change of foam half-life of No. 3—5 foaming agents. The foam half-life of No. 1 foaming agent increased from 70 to 260 min, and that of No. 2 decreased from 60 to 25 min. After 1% crude oil was mixed with 5% No. 1 foaming agent solution, the foam volume reduced from 398 to 388 mL, and the foam half-life decreased from 70 to 7 min, showing good washing oil ability. No. 1 foaming agent sodium alcohol ether sulphate satisfied the requirement of air foam flooding in Changqing oilfield.